Scale Definition and 743 Threads

  1. orazon

    How Does a Pulley System Affect Scale Readings?

    A kid is standing on a scale and holding a rope that goes through a pulley, on the other side the rope is connected to a spring and then to a 50N mass item. Assume that the kid's weight is 700N 1. While in static mode - what will the scale show? 2. The kid is now pulling the rope to get the mass...
  2. C

    I Error on a weighing scale due to wrong size

    If you have say a 15 centimetre long piece of rigid plastic and the weighing scale's tray is only 10 centimetres, what is an estimate of the error that introduces in the measurement assuming the weight is still within normal parameters for the weighing scale. I was wondering what the approximate...
  3. S

    Which key or scale? Dm, Gmaj, Cmaj, (maybe with B-flat-maj)

    I have tried a web search and poked through some scales and chord set using an instrument, but I cannot make formal sense of a song which uses Dminor, Gmaj, Cmaj, and seems to but not sure also includes B flat majr. My musical knowledge is limited. What key or scale relies on this set of...
  4. bob012345

    Milestones of a human lifetime on a log scale

    In another thread the concept of how many seconds in a year came up and it made me think of putting milestones of a human lifetime on a log scale. Units are seconds. Please feel free to amend or change or just make it better. Maybe an actual plot? What strikes me is most of life is in the last...
  5. W

    B Where Are the To-Scale Diagrams of Alpha Centauri's Orbits?

    I sometimes get surprised by things that do not seem to exist in this world. For example, as far as I know, nobody has ever, during the entire history of photography, made a photographic time-lapse of lunar libration. There are plenty of computer renderings, but no photographic time-lapse...
  6. DrDavy

    B Can an Hourglass on a Balance Scale Create Equilibrium?

    Here's my question: Two spent hourglasses that weigh exactly the same on a balance scale. You flip one over so that it's running. What happens to the balance?
  7. P

    Acceleration of a person jumping off of a bathroom scale

    fnet=ma Fn-fg=ma 840 - (72)(-9.8) = 72a a= 840 - (-705.6) /72 a=21.19m/s^2 The correct answer is 1.9m/s^2 unsure of how to get that
  8. Safinaz

    A The scale of an extra dimension

    Any help to understand how the authors of this paper Fine Tuning Problem of the Cosmological Constant in a Generalized Randall-Sundrum Model calculted this size of the extra dimension Equ. (3.8) from the scale factor defined by Equ. (3.3) ? Specifically, this paragraph after Equ. (3.8) -...
  9. M

    A Confusion of the scale of contact line dynamics and capillary flow

    I'm having some trouble getting my head around the scale at which capillary flow and contact line dynamics are important. In the simple case of liquid rise in a capillary tube, a smaller tube will allow for greater rise since a larger height is required to achieve an equal weight of the liquid...
  10. E

    B Upwards movement -- Lifting weights while standing on a scale

    if I move a weight upwards, will the force exerted on my feet change? I tried standing on scales and lifting a weight but nothing changed as the force seemed to be all in my arm muscles and no change in the weight on the scales...
  11. jordy1113

    I How is the sound horizon at recombination and BAO measured in the CMB?

    So I'm trying to understand the sound horizon measured at recombination and the sound horizon measured with BAO. Here is what I've gathered (PLEASE tell me if I'm wrong and if you could please explain, I've been trying to read but can't find a clear explanation): ~r(z*) is measured using CMB...
  12. G

    B Does Light Energy contain Heat Energy in a large scale?

    Can I understand that light energy contains heat energy? or Do I have to separate between two concepts? because light energy from the sun makes heat energy after absorption of molecular?
  13. S

    Weight of gold chain when dropped on a weighing scale

    The force exerted downwards on the scale by the chain when it is kept on it would be Fg= Mg =λLg where λ is the linear mass density However when the chain is dropped onto the scale it exerts an additional force due to its change in momentum The force exerted by each part of the chain would...
  14. Ineedhelpwithphysics

    Action Reaction Spring Scale Question

    Here is the image the answer is say 100 but why. Why isn't it 0. Is it because of the pulley but even with the pulleys the tensions in both ropes are 100 N.
  15. N

    B Vector of forces (question about how a scale works)

    so my question is a little dumb, if an object on a scale has a weight that points downwards and the scale exert normal force on the object upwards cancelling the forces acted on the object then what does the scale read? also the action-reaction pair to the normal force is supposed to be the...
  16. jedishrfu

    PSA Dont scale a cliff while on a hike

    Hiker attempts to scale a vertical wall with his trusty helicopter as backup. https://unofficialnetworks.com/2021/11/11/stuck-hiker-cliff-helicopter/
  17. Sagittarius A-Star

    I Force on Scale in Rocket Scenario: Calculation & Discussion

    [Moderator's note: Spin-off posts from previous thread have been included in this new thread. Also, the OP's re-post of the scenario for discussion has been moved to this top post for clarity.] Yes. Physically, scales measure a force (and indirectly the energy) in their frame. Consider the...
  18. AHSAN MUJTABA

    I Dimensions of Cosmic Scale Factor ##a(t)##

    I know the formula for Hubble's parameter, ##\frac{\dot{a}}{a}##, but I cannot infer any dimension of ##a(t)## from it. Please guide me. Thanks.
  19. T

    I Large scale entanglement experiment

    This is the paper and here is the video. As far as I know, this is an entanglement related experiment done so far in such a large scale. I want to know whether entanglement related experiment has been done so far on a larger scale and what can be the possible use of such phenomenons.
  20. M

    Thermal time scale in tubular flow reactors

    So if I have a tubular reactor for nanoparticle synthesis (PTFE tubes ID:2mm). The tubes are heated in a furnace. liquid Reagents at room temperature are pumped by a syringe pump and directed toward the furnace. The reagents decompose to form nanoparticles once they reach the steady-state...
  21. K

    Iron block dropped into a container of water sitting on a scale

    Does the scale change during the block sinks? I am so confused... Is there any difference on change of scale with the applying of drag force?
  22. FEAnalyst

    I Logarithmic scale - interpolation

    Hi, knowing the coordinates of two points: ##(x_1,y_1)## and ##(x_2,y_2)## on a linear scale plot, I can use linear interpolation to get ##y## for a point of known ##x## using the formula below: $$y=y_1+(x−x_1) \frac{(y_2−y_1)}{(x_2−x_1)}$$ But how does it look like in the case of logarithmic...
  23. B

    How to format x axis to a smaller scale in Gnuplot?

    So here is what I'm trying to do. The values on x-axis are from 10000, 20000, 30000, ... 100000. I'm trying to write it like this: 10, 20, 30, 40, ... 100 (only x axis) But how do I do this? I've tried those two examples How to scale the axis in Gnuplot, How to scale the axes in Gnuplot but...
  24. George Keeling

    I Is Scale Factor a Scalar? Sean Carroll Invitation

    Is the scale factor a scalar? I think that the answer is no but I want to check because god (or the universe) has been playing tricks on me... At Sean Carroll's invitation I wanted to check that the tensor$$ K_{\mu\nu}=a^2\left(g_{\mu\nu}+U_\mu U_\nu\right) $$was a Killing tensor...
  25. S

    MHB What is the ratio between sides of two triangles with lengths 6 and 15?

    Can someone please help me with these questions? I would be extremely thankful!
  26. brotherbobby

    Scale height ##z_0## of atmosphere's density profile

    I want to begin by writing the problem and drawing its sketch to make things clearer on what is being asked for. Given : In the sketch shown to the right, the density profile of air with increasing ##z## is given by ##\rho=\rho_0 \exp(-z/z_0)##. Since we know the value of atmospheric pressure...
  27. bagasme

    Why We Learn Reaumur Temperature Scale in High School Physics

    Hi, In high school physics I learned how to convert between Celcius, Fahrenheit, Kelvin, and Reaumur scale of temperature. While the first three scales are highly used, why do we learn the fourth scale (Reaumur) when there aren't any practical use of it? Just for formality? Bagas
  28. Arman777

    I Is Scale Factor Continuity and Differentiability Necessary?

    Does scale factor must be continuous(Con.) and differentiable (Diff.) ? Or can it be one of them or neither ? Physically one expects it to be Con. and Diff. but is there a more rigorous proof. And as a separate question, if ##\dot{a}## is not continuous/differentiable in some case, does that...
  29. F

    B Cold vs hot on the atomic scale

    So I've been hunting google for an answer but i cannot find a definitive one. If 0 Kelvin is the coldest temperature and it is where atoms cease to move does this mean that a photon in a vacuum is the hottest particle because it is in turn moving at the fastest speed possible? Second question...
  30. AHSAN MUJTABA

    Scale Factor & ##\Omega##: Finding the Relation

    I am trying to develop a relation between scale factor (a(t)) and ##\Omega##. The relation came out to be evolve as ##\Omega_i=\Omega_io * a^{-n}## but my graph isn't right it's giving values of ##a(t)## to higher extent. I consulted my instructor he only added that I should include ##H_o##...
  31. greg_rack

    Tension measured by a voltmeter of given bottom scale and current range

    First and foremost, I've studied voltmeters and ammeters on my own, and online there aren't many resources to do so... forgive me in advance for eventual silly questions/doubts :) I managed to calculate(intuitively) a tension of ##30.0V## per resistor, with basic procedures. However, I'm...
  32. F

    I Plotting polar equations and scale invariance

    Hello, In the plane, using Cartesian coordinates ##x## and ##y##, an equation (or a function) is a relationship between the ##x## and ##y## variables expressed as ##y=f(x)##. The variable ##y## is usually the dependent variable while ##x## is the independent variable. The polar coordinates...
  33. T

    B Why is an inverse logarithmic scale chosen for the magnitudes of stars?

    Star magnitudes of brightness seem to use inverse logarithmic scales, is there a benefit to this? Why was this chosen, i can understand logarithmic might make it easier to interpret data in same way we do similar for earthquakes etc. But why inverse ? When i look at a HR diagram for example (...
  34. R

    B Modern Cavendish vs LIGO: Gravity Scale & Wave Interruption?

    What is the scale of magnitude of gravity, that a modern Cavendish like laser detector of gravity pull between small daily size objects can detect in comparison to the magnitude of gravitational wave a LIGO like detector can detect? Will such a modern Cavendish like device measurements be...
  35. tomdodd4598

    I Renormalisation scale and running of the φ^3 coupling constant

    I am still rather new to renormalising QFT, still using the cut-off scheme with counterterms, and have only looked at the ##\varphi^4## model to one loop order (in 4D). In that case, I can renormalise with a counterterm to the one-loop four-point 1PI diagram at a certain energy scale. I can...
  36. S

    Most accurate scale for weighing objects

    Hello, What is the most accurate weighting scale in existence and what kind to look for if you want accuracy. The other day I got this scale. I put a known 7.6 pound book. It showed up as 7.730 lbs so I returned it. I need something that can show exactly the weight. What kinds of scale must I...
  37. W

    B Nearly Scale Invariant Power Spectrum in inflation

    I recall hearing once a very intuitive explanation as to why inflation is thought to lead to a nearly scale invariant power spectrum but i can't recall it. Can anyone offer an explanation that might help me? Why is it nearly scale invariant and not perfectly scale invariant? many thanks
  38. Lren Zvsm

    Asimov's Psychohistory: Possible on a sufficiently large scale?

    As we all learned a long time ago, the trajectories of individual air molecules can't be predicted, but the behavior of macroscopic air masses can be predicted--if imperfectly, as with weather forecasts. Similarly, the behavior of human individuals isn't always predictable. The less well...
  39. Rakshitgarg1709

    Understanding How to Scale an Atom's Nucleus

    Actually i was solving a basic physics problem that says : an atom has nucleus size 10^-15m and it is scaled upto the tip of pin 10^-5m . tell the size of atom. I saw this ques already solved here but i just can't understand how size of nucleus can be increased,...
  40. J

    Weight Scale Logic: Solving Problems without Calculation

    [mentor note: edited for clarity] The man weighs 100kg. All constructions, ropes, universal joints, rollers, fans, etc are massless. Friction between weight scale and feet or construction is enough to hold side forces... The red line is the rope. What will the weight scale show? <100kg...
  41. jaumzaum

    B Learn Special Relativity: Understanding Graphs for X-T System

    Hello guys! I just started to learn Special Relativity though a Stanford youtube channel, and I had some problems already in the first class :oops: The teacher drew a graph with one spatial dimension (x-axis) and one temporal dimension (t-axis). Where X is the horizontal axis, T is the vertical...
  42. jugren

    Nuclear Chain Reaction Conditions

    Hi all, For my studies I chose a course on scaling up and down of industrial processes (mostly focussed on the chemical industry), but for our project we (a group of students who knew almost nothing about nuclear reactors) chose to look if the approach (dimensional analysis) can be applied to...
  43. scottdave

    B Using a logarithmic scale to represent COVID-19 growth

    The author, John Burn-Murdoch, shows here ( https://threadreaderapp.com/thread/1237748598051409921.html ) how the logarithmic scale can give a better "sense" of what is happening. In linear scales, some countries' data is squashed to almost nonexistent, while others explode out of control. I...
  44. r12214001

    Using Energy Conservation to solve this problem: Jumping on a spring scale

    I suppose spring compression to be X when jumpping from 1m. Therefore gravational potential mgh=760(1+X) and my cal:760(1+X)=0.5kX² why the solution manual state that 760=0.5kX²+760X
  45. R

    B Scale of Measurement vs Equipment Sensitivity: Does Symmetry Always Hold?

    Many times when i ask about test theories of SR, i am reminded by forum members, that equipment sensitivity, is equivalent to producing more extreme physical values. For example, you don't necessarily have to go faster in speed, in order to have a better measurement of time dilation, if you have...
  46. M

    MHB Find the scale factor of triangle ABC to triangle DEF

    Triangles ABC and DEF are similar. Triangle ABC has a perimeter of 16cm. Triangle DEF has side of 6cm, 8cm and 10cm. What is the scale factor of triangle ABC to triangle DEF? A. 1/2 B. 1/3 C. 2/3 D. 3/2 E. 2/1 I concluded the answer is D. Am I correct?
  47. B

    New full scale deflection of an ammeter

    Question: My attempt: Does 4.75 amps for the full scale deflection seem okay? Thanks for any help!
  48. L

    Engineering How would an alarm button work in a bathroom scale?

    All I know is that when you press the button, the LCD icon displays an alarm icon which indicates the alarm has been programmed to sound at the exact time every 24 hours.
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